Polyoxyalkylene derivative

A polyoxyalkylene derivative represented by the following formula (1)

• wherein
• Z is a peptide residue consisting of 2 to 10 amino acid residues, wherein one or more amino acid residues have a side chain containing a functional group,
• OA is an oxyalkylene group having 2 to 4 carbon atoms,
• R is a hydrogen atom or a hydrocarbon group having 1 to 4 carbon atoms,
• X1 and X2 are groups containing a succinimide group, a maleimide group, an amino group, a carboxyl group, a carbonate group, an aldehyde group, a sulfonyl group, a thiol group, a vinyl group, an allyl group or a hydroxyl group,
• Y and W are each independently a divalent group containing a group selected from the group consisting of
• —CONH—, —NHCO—, —OCONH—, —NHOCO—, —COO—, —OOC—, —COS—, —SOC—, —CH2NH—, —NHCH2—, —S—CH<, >CH—S—, —CH2—S—, —S—CH2—, —S—S— and —O—,
• n is an integer of 5-1000, m is an integer of 5-800, j1 is an integer of 0-12, j2 is an integer of 0-8, k is an integer of 0-11, wherein 1<j1+j2≦12, 2≦k+j1≦12, 3≦k+j1+j2≦12, 30≦(n×k)+(m×j1)≦2000.